The present disclosure relates to gas turbine engine architecture, and more particularly to a variable cycle architecture.
Variable cycle gas turbine engines power aircraft over a range of operating conditions yet achieve countervailing objectives such as high specific thrust and low fuel consumption. The variable cycle gas turbine engine essentially alters a bypass ratio during flight to match requirements. This facilitates efficient performance over a broad range of altitudes and flight conditions to generate high thrust for high-energy maneuvers yet optimize fuel efficiency for cruise and loiter operational modes.
The countervailing objectives that enable a variable cycle requires an architecture that avoids overly high temperatures upstream of the combustor section (T3) at takeoff yet also provides a high overall pressure ratio (OPR) at high altitude cruise.